Obesity in the Asia-Pacific body mass index classification is associated with the development of chronic kidney disease in non-diabetic Japanese men and women

Abstract

Background/ObjectivesObesity is a risk factor for the development of chronic kidney disease (CKD). However, little is known about the relationship between the Asia-Pacific body mass index classification (Asia-Pacific classification) and the subsequent development of CKD in non-diabetic Asian men and women.Subjects/MethodsBody mass index (BMI) was categorized in accordance with the Asia-Pacific classification: underweight (< 18.5 kg/m2), normal weight (18.5–22.9 kg/m2), overweight (23.0–24.9 kg/m2), obesity class I (25.0–29.9 kg/m2), and obesity class II (≥ 30.0 kg/m2). Using administrative checkup data for non-diabetic Japanese adults (1998–2023), we assessed the relationship between the Asia-Pacific classification and new-onset CKD by sex. The Weibull accelerated failure time model was selected because the proportional hazards assumption was violated.ResultsIn total, 34.2% of 3,098 men and 34.8% of 4,391 women had newly developed CKD. The mean follow-up time was 7.41 person-years for men and 8.25 person-years for women. Compared with those of normal weight, obesity class I was associated with a 6% (95% confidence interval [CI]: 2%–10%) shorter time to CKD development in men and a 6% (95% CI: 2%–9%) shorter time to CKD development in women. Obesity class II was associated with the shortest survival to CKD onset by point estimate in men but had an almost null value in women (i.e., 95% CIs crossed 1 in all of the models).ConclusionsAmong non-diabetic Japanese men and women, obesity class I in the Asia-Pacific classification was associated with a shorter survival time to CKD onset than normal weight. Low point estimates for obesity class II suggested a dose-response relationship in men but a less clear relationship in women. The conventional cutoff value for obesity, BMI ≥ 30.0 kg/m2, may be too high a risk factor for new-onset CKD in non-diabetic Asians, regardless of sex.